Mediterranean Diet Demonstrates Significant Positive Impacts on Cognition in Multiple Sclerosis

Ilana Sand, MD

Data from a cohort of patients with multiple sclerosis (MS) revealed significant associations between higher adherence to Mediterranean diet and cognition, suggesting the possibility of a neuroprotective mechanism.

Led by Ilana K. Sand, MD, associate professor of neurology, Mount Sinai, the trial featured 563 individuals with MS who completed the Mediterranean Diet Adherence Screener (MEDAS) and an analogue of the popular Brief International Cognitive Assessment for MS (BICAMS) test. Patients scored 0-14 on MEDAS while also completing additional measures such as Symbol Digit Modalities Test (SDMT), Hopkins Verbal Learning Test-Revised, and CANTAB Paired Associate Learning.

Presented at the 2023 American Academy of Neurology (AAN) Annual Meeting, held April 22-27, in Boston, Massachusetts, mean composite cognitive z-scores were –0.67 (±0.95), with higher MEDAS independently predicting better cognition (B = 0.08; 95% CI, 0.05-0.11; ß = 20; P <.001) after adjustment. In the trial, Sand et al investigated the independent contribution of MEDAS to cognition by adjusting for demographic factors of age, sex, race, ethnicity, and socioeconomic status, as well as health-related factors of body mass index, exercise, sleep disturbance, hypertension, diabetes, hyperlipidemia, and smoking.

Slightly less than 20% (19.2%) of patients demonstrated cognitive impairment, as higher MEDAS scores independently predicted 20% lower risk for cognitive impairment (OR, 0.80; 95% CI, 0.73-0.89; P <.001). Furthermore, MEDAS was found to be the best health-related predictor of cognitive z-score and cognition impairment. The associations between z-score and impairment were even stronger for those with progressive disease vs those with more relapsing forms.

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Sand and her colleagues concluded that additional, more longitudinal studies are needed to further confirm these findings; however, this was not the first time Mediterranean diet was associated with cognition. In 2022, a large-scale cohort study of 6321 Hispanic or Latino adults showed that a high level of adherence to this diet was associated with better global cognition and decreased 7-year learning and memory decline relative to those with a low level of adherence.²

In a 2018 review of the role of diet in MS, Sand noted there are several theoretical pathways through which dietary factors may exert systemic influence resulting in beneficial effects on inflammation, neuroprotection, and repair in MS. Specifically, diet has a significant impact on body weight, cholesterol levels, and other vascular risk factors that affect MS risk and disease course. Part of the issue is separating the relative contribution of diet from these other factors, which will require additional studies.

In that paper, Sand concluded "While some factors are well described, the contribution of other mediators has not been fully elucidated. The initial epidemiologic investigations regarding a potential role for diet in MS date back many years. More recently, preclinical models, epidemiologic research, a small number of prospective studies, and limited clinical trials suggest the importance of various dietary factors in MS. Mechanistic experiments highlight potential effects of diet on both immunomodulatory and neurodegenerative processes in MS."³

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REFERENCES
1. Sand IK, Fitzgerald K, Sumowski J. Mediterranean diet is associated with cognition in multiple sclerosis. Presented at: 2023 AAN Annual Meeting; April 22-27; Boston, MA. Abstract 004052
2. Moustafa B, Trifan B, Isasi CR, et al. Association of Mediterranean diet with cognitive decline among diverse Hispanic or Latino adults from the Hispanic community health study/study of Latinos. JAMA Netw Open. 2022;5(7):e2221982. doi:10.1001/jamanetworkopen.2022.21982
3. Sand IK. The role of diet in multiple sclerosis: mechanistic connections and current evidence. Current Nutrition Reports. 2018;7:150-180. doi:10.1007/s13668-018-0236